Evaluation of physical and morphometric parameters for water resource management in Gad Watershed,Western Ghats,India: an integrated geoinformatics approach     

Sandeep Mahajan  R. Sivakumar 《Environmental Earth Sciences》2018,77(15):556

The selected study area is a coastal watershed which receives high rainfall in the monsoon season. During this period, most of the water input to the watershed drains to the Arabian Sea without any adequate use due to the rugged topography of the watershed. Hence, an attempt has been made to assess the physical properties specifically morphometric parameters of the Gad watershed using geoinformatics techniques along with field evidence for understanding the relationship between fluvial landforms and hydro-physical parameters in the region. Morphometric parameters have been analyzed and integrated with physical parameters like topography, rainfall, soil, land use–land cover, geology, and geomorphology for evaluating the potential water resource availability in the Gad watershed. The results of the study have shown that there is high surface water availability in the watershed with very low water retaining capacity, mainly in the upper region of the watershed due to presence of basaltic bedrock and steep slopes. Based on this work, a water resource management plan has been suggested at a subwatershed level which established on the physical properties and morphological characteristics of the study area.  相似文献   

Analyzing rainfall seasonality and trends in the North Maharashtra region     

S. T. Ingle  S. N. Patil  N. K. Mahale  Y. J. Mahajan 《Environmental Earth Sciences》2018,77(18):651

The North Maharashtra region comprises three districts, namely Jalgaon, Dhule, and Nandurbar. The region comprises 25 talukas, which are mostly covered by agricultural fields. Seasonality and trend analysis of rainfall over North Maharashtra region from 1901 to 2016 is conducted in the present work. The data were analyzed on the basis of season, i.e. winter, pre-monsoon, monsoon, and post monsoon. For trend detection, the Sen’s slope estimator and the Mann–Kendall test are used. The largest negative rainfall trends are found in the talukas Nandurbar and Jamner. In Akkalkuwa, the strongest positive trend is found. The rainfall trends in the recent years are discussed in the present work.  相似文献   

Santa Lucia (2008) (L6) Chondrite,a Recent Fall: Composition,Noble Gases,Nitrogen and Cosmic Ray Exposure Age     

Ramakant R. Mahajan  Maria Eugenia Varela  Jean Louis Joron 《Earth, Moon, and Planets》2016,117(2-3):65-76

  相似文献   

Exact Delaunay normalization of the perturbed Keplerian Hamiltonian with tesseral harmonics     

Bharat Mahajan  Srinivas R. Vadali  Kyle T. Alfriend 《Celestial Mechanics and Dynamical Astronomy》2018,130(3):25

A novel approach for the exact Delaunay normalization of the perturbed Keplerian Hamiltonian with tesseral and sectorial spherical harmonics is presented in this work. It is shown that the exact solution for the Delaunay normalization can be reduced to quadratures by the application of Deprit’s Lie-transform-based perturbation method. Two different series representations of the quadratures, one in powers of the eccentricity and the other in powers of the ratio of the Earth’s angular velocity to the satellite’s mean motion, are derived. The latter series representation produces expressions for the short-period variations that are similar to those obtained from the conventional method of relegation. Alternatively, the quadratures can be evaluated numerically, resulting in more compact expressions for the short-period variations that are valid for an elliptic orbit with an arbitrary value of the eccentricity. Using the proposed methodology for the Delaunay normalization, generalized expressions for the short-period variations of the equinoctial orbital elements, valid for an arbitrary tesseral or sectorial harmonic, are derived. The result is a compact unified artificial satellite theory for the sub-synchronous and super-synchronous orbit regimes, which is nonsingular for the resonant orbits, and is closed-form in the eccentricity as well. The accuracy of the proposed theory is validated by comparison with numerical orbit propagations.  相似文献   

Photometric and spectroscopic observations of three rapidly rotating late‐type stars: EY Dra,V374 Peg,and GSC 02038‐00293     

H. Korhonen  K. Vida  M. Husarik  S. Mahajan  D. Szczygie&#x;  K. Olh 《Astronomische Nachrichten》2010,331(8):772-780

Here, BV (RI)_C broad band photometry and intermediate resolution spectroscopy in H_α region are presented for two rapidly rotating late‐type stars: EY Dra and V374 Peg. For a third rapid rotator, GSC 02038‐00293, intermediate resolution H_α spectroscopy and low resolution spectroscopy are used for spectral classification and stellar parameter investigation of this poorly known object. The low resolution spectrum of GSC 02038‐00293 clearly indicates that it is a K‐type star. Its intermediate resolution spectrum can be best fitted with a model with T_eff = 4750 K and v sin i = 90 km s^–1, indicating a very rapidly rotating mid‐K star. The H_α line strength is variable, indicating changing chromospheric emission on GSC 02038‐00293. In the case of EY Dra and V374 Peg, the stellar activity in the photosphere is investigated from the photometric observations, and in the chromosphere from the H_α line. The enhanced chromospheric emission in EY Dra correlates well with the location of the photospheric active regions, indicating that these features are spatially collocated. Hints of this behaviour are also seen in V374 Peg, but it cannot be confirmed from the current data. The photospheric activity patterns in EY Dra are stable during one observing run lasting several nights, whereas in V374 Peg large night‐tonight variations are seen. Two large flares, one in the H_α observations and one from the broadband photometry, and twelve smaller ones were detected in V374 Peg during the observations spanning nine nights. The energy of the photometrically detected largest flare is estimated to be 4.25 × 10³¹– 4.3 × 10³² erg, depending on the waveband. Comparing the activity patterns in these two stars, which are just below and above the mass limit of full convection, is crucial for understanding dynamo operation in stars with different internal structures (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Seasonal characteristics of tropical marine boundary layer air measured at the Cape Verde Atmospheric Observatory     

L. J. Carpenter  Z. L. Fleming  K. A. Read  J. D. Lee  S. J. Moller  J. R. Hopkins  R. M. Purvis  A. C. Lewis  K. Müller  B. Heinold  H. Herrmann  K. Wadinga Fomba  D. van Pinxteren  C. Müller  I. Tegen  A. Wiedensohler  T. Müller  N. Niedermeier  E. P. Achterberg  M. D. Patey  E. A. Kozlova  M. Heimann  D. E. Heard  J. M. C. Plane  A. Mahajan  H. Oetjen  T. Ingham  D. Stone  L. K. Whalley  M. J. Evans  M. J. Pilling  R. J. Leigh  P. S. Monks  A. Karunaharan  S. Vaughan  S. R. Arnold  J. Tschritter  D. Pöhler  U. Frieß  R. Holla  L. M. Mendes  H. Lopez  B. Faria  A. J. Manning  D. W. R. Wallace 《Journal of Atmospheric Chemistry》2010,67(2-3):87-140

Observations of the tropical atmosphere are fundamental to the understanding of global changes in air quality, atmospheric oxidation capacity and climate, yet the tropics are under-populated with long-term measurements. The first three years (October 2006–September 2009) of meteorological, trace gas and particulate data from the global WMO/Global Atmospheric Watch (GAW) Cape Verde Atmospheric Observatory Humberto Duarte Fonseca (CVAO; 16° 51′ N, 24° 52′ W) are presented, along with a characterisation of the origin and pathways of air masses arriving at the station using the NAME dispersion model and simulations of dust deposition using the COSMO-MUSCAT dust model. The observations show a strong influence from Saharan dust in winter with a maximum in super-micron aerosol and particulate iron and aluminium. The dust model results match the magnitude and daily variations of dust events, but in the region of the CVAO underestimate the measured aerosol optical thickness (AOT) because of contributions from other aerosol. The NAME model also captured the dust events, giving confidence in its ability to correctly identify air mass origins and pathways in this region. Dissolution experiments on collected dust samples showed a strong correlation between soluble Fe and Al and measured solubilities were lower at high atmospheric dust concentrations. Fine mode aerosol at the CVAO contains a significant fraction of non-sea salt components including dicarboxylic acids, methanesulfonic acid and aliphatic amines, all believed to be of oceanic origin. A marine influence is also apparent in the year-round presence of iodine and bromine monoxide (IO and BrO), with IO suggested to be confined mainly to the surface few hundred metres but BrO well mixed in the boundary layer. Enhanced CO₂ and CH₄ and depleted oxygen concentrations are markers for air-sea exchange over the nearby northwest African coastal upwelling area. Long-range transport results in generally higher levels of O₃ and anthropogenic non-methane hydrocarbons (NMHC) in air originating from North America. Ozone/CO ratios were highest (up to 0.42) in relatively fresh European air masses. In air heavily influenced by Saharan dust the O₃/CO ratio was as low as 0.13, possibly indicating O₃ uptake to dust. Nitrogen oxides (NO_x and NO_y) show generally higher concentrations in winter when air mass origins are predominantly from Africa. High photochemical activity at the site is shown by maximum spring/summer concentrations of OH and HO₂ of 9?×?10⁶ molecule cm^?3 and 6?×?10⁸ molecule cm^?3, respectively. After the primary photolysis source, the most important controls on the HO_x budget in this region are IO and BrO chemistry, the abundance of HCHO, and uptake of HO_x to aerosol.  相似文献   

Probabilistic seismic hazard map of NW Himalaya and its adjoining area,India   总被引：2，自引：1，他引：1  

A. K. Mahajan  V. C. Thakur  Mukat Lal Sharma  Mukesh Chauhan 《Natural Hazards》2010,53(3):443-457

The seismically active Northwest (NW) Himalaya falls within Seismic Zone IV and V of the hazard zonation map of India. The region has suffered several moderate (~25), large-to-great earthquakes (~4) since Assam earthquake of 1897. In view of the major advancement made in understanding the seismicity and seismotectonics of this region during the last two decades, an updated probabilistic seismic hazard map of NW Himalaya and its adjoining areas covering 28–34°N and 74–82°E is prepared. The northwest Himalaya and its adjoining area is divided into nineteen different seismogenic source zones; and two different region-specific attenuation relationships have been used for seismic hazard assessment. The peak ground acceleration (PGA) estimated for 10% probability of exceedance in 50 and 10 years at locations defined in the grid of 0.25 × 0.25°. The computed seismic hazard map reveals longitudinal variation in hazard level along the NW Himalayan arc. The high hazard potential zones are centred around Kashmir region (0.70 g/0.35 g), Kangra region (0.50 g/0.020 g), Kaurik-Spitti region (0.45 g/0.20 g), Garhwal region (0.50 g/0.20 g) and Darchula region (0.50 g/0.20 g) with intervening low hazard area of the order of 0.25 g/0.02 g for 10% probability in 50 and 10 years in each region respectively.  相似文献   

Rainfall and anthropogenically accelerated mass movement in the Outer Himalaya,north of Dharamshala town,Kangra district,Himachal Pradesh: A cause of concern     

Rajwant Sharma  Umesh Kumar Sharma  A.K. Mahajan 《Journal of the Geological Society of India》2015,86(5):563-569

  相似文献   

Response of Venus ions to solar wind dynamic pressure     

Hari Om Upadhyay  K. K. Mahajan 《Earth, Moon, and Planets》1996,74(3):215-222

Orbiter ion mass spectrometer measurements, as available in the UADS data files are used to study the response of dayside Venus ions at various altitudes to solar wind dynamic pressure, P _sw. Ion densities below about 200 km are not affected by changes in P _sw. At altitudes above 200 km the ions get abruptly depleted with increase in P _sw, and this abrupt depletion occurs at lower altitudes when P _sw is high. At lower P _sw, the depletion occurs at higher altitudes. The effect is similar for all ions. These results are also compared with the empirical relationship observed by Brace et al. (1980) between the ionopause altitude and P _sw from electron density measurements on orbiter electron temperature probe.  相似文献   

Self-focusing of electromagnetic radiation in electron-positron ion plasma     

V. I. Berezhiani  S. M. Mahajan 《Astrophysics and Space Science》1994,222(1-2):241-246

We consider the self-focusing of electromagnetic (EM) radiation in electron-positron plasmas with a small fraction of ions. It is shown that in such a plasma EM pulses may form and propagate like oscillatory waveguides.  相似文献